rationalskepticism.org

tuco wrote:So .. I am making bigger holes? What's in them? I don't like making matter without energy.

Are you being facetious? Perhaps preying on an imperfect analogy?

The universe is expanding because for some crazy unknown reason it started expanding at the big bang. Gravity is slowing it down by. . . being gravity. At a certain density the matter in the universe should be enough to let gravity take over and collapse everything back again.

However, our observations of galaxies orbiting each other threw a bit of a kink in this. Given the mass contained in any given galaxy we can calculate how they should orbit another galaxy. We actually observe them orbiting as though they contained more mass- mass we didn't account for because we couldn't see it. The only explanation is there must be some kind of mass which interacts with virtually NOTHING. It doesn't reflect light, it doesn't bump into atoms- nothing. This is what we call dark matter. The problem is if we plug dark matter into the equation we get a universe too heavy to keep expanding. Our best observations indicate the expansion is speeding up, not slowing down. It's postulated, then, that there must be a dark energy which works on a universal scale to push everything apart.

Even though the universe is expanding we don't see the objects around us increase in size proportionally because gravity is still doing its thing keeping everything together. In billions of years nothing will have changed but the distance between the islands where gravity is strong enough to overcome the expansion- galaxies. As the expansion speeds up, however, so too does the amount of mass needed to have gravity overcome this and keep everything stuck together. Eventually, it will slowly rip galaxies apart. After that, it will pull on atoms themselves until it is stronger than the forces holding THOSE together and the universe becomes devoid of everything we consider matter. Because heat is a function of how fast atoms are wiggling around and because more space means more space to wiggle, and therefore less heat, this is referred to as "heat death".

So to explain the properties of space further:
"Space" describes an aspect of the universe just as "south" describes an aspect of movement in relation to a finite sphere (or any other object, really). They are both descriptions or labels of properties. They are a way for our mind to make sense of what's around us and hierarchically sort things out. Passing beyond or outside the subject makes the description of that aspect invalid. There is nothing south of the south pole because south describes how to move about the earth. Leaving the earth makes that description invalid because you're not dealing with something that contains that property as you understood it before. Passing outside of the universe is the same thing in regards to both space and time. They are descriptions of aspects which no longer apply.

It's not even that there is nothing there. It's not even "nothing". It's just. . . nothing. There is no proper word to describe it. It's not an empty existence, it's the lack of any existence at all.


All that being said . . .

The expansion of space is just a thing the universe is doing. We know what it is, we can look at it, and we can sort out what we think it's going to do as time goes on. It's not even that hard to understand once you know how it interacts with everything else.